Effect of Oxidation Time on Electrodeposited Iron Aluminum OxideNanoparticles

*Sajid ur Rehman1), Saira Riaz2), S. Sajjad Hussain3), Y.B. Xu4)

and Shahzad Naseem5)

1), 2), 3), 5) Centre of Excellence in Solid State Physics, University of Punjab, Lahore,Pakistan

4) Department of Electronics, University of York, UK2) saira.cssp@pu.edu.pk

ABSTRACT

Iron aluminum oxide nanoparticles are prepared using electrodepositiontechnique. Electrodeposition voltage and time is kept fixed i.e. 2V and 10 minutes,whereas, oxidation time is varied as 5 – 15 minutes. To reveal the structural andmagnetic properties of iron aluminum oxide nanoparticles X-ray diffraction and vibratingsample magnetometer are used. It is observed from XRD patterns that all thenanoparticles exhibit spinel structure. Crystallite size increases from 20.5nm to 22.4nmnm as oxidation time is increased from 5min to 15min. Increase in crystallite size isaccompanied by decrease in dislocation density. Iron aluminum oxide nanoparticlesexhibit ferromagnetic behavior with highest saturation magnetization of 1.0791×10-3

emu for nanoparticles synthesized at 15min oxidation time. Increase in crystallite sizewith increase in oxidation time leads to increase in saturation magnetization anddecrease in coercivity of iron aluminum oxide nanoparticles.

1. INTRODUCTION

Ferrites are magnetic materials having electrical and magnetic properties. Crucialcomponents of ferrites are iron oxide and metal oxides (Bas et al. 2003). Iron aluminumoxide is selected owing to its unique and novel properties (Booker et al. 2005). Ironoxide based compounds are efficient in order to increase and/or vary magneticproperties of its associated materials. Iron oxide plays vital role in various fields ofscience and technology (Cullity 1956). It occurs in sixteen different phases and ispresent in large amounts in earth’s crust. It is used extensively as electrode in alkalineand non-aqueous media and is also used as cathode in brine electrolysis (Holland et al.1965). Due to distinctive properties of Fe2O3 such as large response time and largeoptical susceptibility, it is most broadly used in optical computing (Kim et al. 2010). Itscatalytic properties make it valuable for nitrogen fixation (Krifa et al. 2013). Inelectronics, these are often used as pigments for super capacitors, photoelectrochemical cells, thermosensors and spintronic devices (Maissel et al. 1970,Paesano et al. 2003). In biomedical science they are used for drug delivery. The mainaim of this work is preparation of iron aluminum oxide nanoparticles with the help of

electrodeposition, which is inexpensive technique (Shinde et al. 2011, Shwarsctein et al.2010).

Iron aluminium oxide belongs to the class of materials that is known as spinelferrites. Thermal stability and specific magnetic properties make spinel ferrites veryimportant ferrites (Siddique et al. 2010, Sikandar et al. 2012). It exists in sixteendifferent types of structures in the form of hydroxides, oxides or oxide-hydroxide(Thiemiga et al.2009). Each structure occurs in crystalline from. Owing to their vastrange of applications they are prepared on large scale in the form of thin film, colloidalparticles and powder. Aluminum oxide serves as a catalyst support for many industrialcatalysts, such as those used in hydride sulfurization and some Ziegler-Nattapolymerizations (Wilson et al. 2002, Xu et al. 2014).

Iron aluminum oxide nanostructures were prepared using electrodepositiontechnique. Iron and aluminum metals were deposited by keeping voltage anddeposition time fixed. Different samples were prepared by varying oxidation time from 5- 15mins.

2. Experimental Details

Hydrated aluminum nitrate Al (NO3)3.6H2O, hydrated iron nitrate Fe(NO3)3.9H2Oand boric acid H3BO3 were dissolved in deionized water and stirred by means ofmagnetic stirrers to form electrolyte. Copper was used as cathode for electrodepositionprocess. During electrodeposition, deposition was carried out for 10 minutes and theoxidation time was varied as 5min, 10min and 15min.

These particles were characterized using Bruker D8 Advance X-ray diffractometerand Lakeshore’s 7407 Vibrating Sample Magnetometer.

3. Results and Discussion

XRD pattern for iron aluminum oxide nanoparticles with oxidation time of 5minutes is shown in the Fig. 1. Planes (311), (400) and (331) appeared in XRD patternmatching with JCPDS card no 3-0894. However, peak corresponding to 2θ value of 42.26o having (321) plane matched with Al2O3 (JCPDS card no 4-0880).

Fig. 1 XRD pattern of iron aluminum oxide nanoparticles for oxidation time 5 minutes

XRD pattern of iron aluminum oxide nanoparticles prepared with oxidation time of10 minutes is shown in Fig. 2. XRD pattern shows the appearance of (311), (400), (331)and (620) planes that matched with FeAl2O4. All these values matched with the JCPDScard no 3-0894. However, peak of Al2O3 was still observed at 2θ value of 42.23o

(JCPDS card no 4-0880).

Fig. 2 XRD pattern of iron aluminum oxide nanoparticles for oxidation time of 10minutes

XRD pattern for iron aluminum oxide nanoparticles with oxidation time 15 minutesis shown in Fig. 3. (311), (400), (331), (511) and (620) planesFeAl2O4 (JCPDS card no 3-0894

Fig. 3 XRD pattern of iron aluminum oxide nanoparticles with the oxidation time of 15

The above-mentioned XRD resultscritical role in achieving FeAltime i.e. 5 - 10 mins lattice of ironenough to react and make new bonds in the presence of oxygen. Moreover, loweroxidation times could not address surface activation energy of iron and aluminum whichis required to make new bonds. With increase in oxidation time lattice of iron andaluminum had enough time for surface activation and to produce FeAlaluminum oxide. Preferred orientationoxidation time from 5 to 10-15 mins.

Crystallite size and dislocation density

θ

λ

cos

9.0

Bt =

2

1

t=δ

for iron aluminum oxide nanoparticles with oxidation time 15 minutes(311), (400), (331), (511) and (620) planes are well matched with

0894).

XRD pattern of iron aluminum oxide nanoparticles with the oxidation time of 15minutes

mentioned XRD results show that variation in oxidation timecritical role in achieving FeAl2O4 phase of iron aluminum oxide. For smaller oxidation

10 mins lattice of iron and aluminum was not stable andenough to react and make new bonds in the presence of oxygen. Moreover, loweroxidation times could not address surface activation energy of iron and aluminum which

required to make new bonds. With increase in oxidation time lattice of iron andaluminum had enough time for surface activation and to produce FeAl

Preferred orientation also changed from (331) to (400) with increase in15 mins.

and dislocation density were calculated using Eq

for iron aluminum oxide nanoparticles with oxidation time 15 minutesare well matched with

XRD pattern of iron aluminum oxide nanoparticles with the oxidation time of 15

that variation in oxidation time plays aphase of iron aluminum oxide. For smaller oxidation

and aluminum was not stable and/or was energeticenough to react and make new bonds in the presence of oxygen. Moreover, loweroxidation times could not address surface activation energy of iron and aluminum which

required to make new bonds. With increase in oxidation time lattice of iron andaluminum had enough time for surface activation and to produce FeAl2O4 phase of iron

also changed from (331) to (400) with increase in

calculated using Eqs. 1 and 2.

(1)

(2)

Where, θ represents the diffraction angle, λ is the wavelength (1.5406Å) and B is FullWidth at Half Maximum. Minimum value of crystallite size (Fig. 4) was observed at theoxidation time of 5 minutes and the maximum value for 10 and 15 minutes oxidationtimes. Conversely, dislocation density has the maximum value for oxidation time of 5minutes and has the lowest value for 10 and 15 minutes as shown in Fig. 5.Dislocations in nanoparticles arise due to presence of grain boundaries.

Fig. 4 Variation in crystallite size with oxidation time

Fig. 5 Variation in dislocation density with oxidation time

The lattice parameters for cubic unit cell are given in Eq. 3.

++= 222

24

22sin lkh

a

λθ (3)

With volume given as V=a3 and (hkl) representing the miller indices, latticeparameter has value 8.163Å for 5 minutes oxidation time and for the oxidation time of10-15 minutes has the lowest value. Variation in lattice parameter with oxidation time isshown in the Fig. 6. These lattice parameter values are in good agreement with JCPDScard no. 3-0894.

Fig. 6 variation in lattice parameter with oxidation time

The unit cell volume of nanoparticles can be calculated by taking the cube of thelattice parameter a. Trend of unit cell volume with oxidation time can be understood byFig. 7. The unit cell volume for the 10 and 15 minutes oxidation remains same.

Fig. 7 variation of unit cell volume with oxidation time

X-ray density can be calculated by Eq.(4) as given below.

V

AΣ=

66042.1ρ (4)

Where, ΣA is the sum of atomic weights in the unit cell, ρ is in g/cm3, and V is thevolume of unit cell in Å3. The X-ray density has the same value for 10 and 15 minutesoxidation time.The trend of variation in X-ray density with oxidation time is representedin Fig. 8. Structural paramters of iron aluminum oxide nanoparticles are summerized inTable 1.

Fig. 8 Variation in X-ray density with oxidation time

Table1: Lattice constant (a), unit cell volume (V), X-ray density, Crystallite size,Dislocation density

VSM was used to determine the magnetic properties of these iron aluminumoxide nanoparticles. All the curves were obtained at room temperature. M-H curves forannealed nanoparticles at room temperature are plotted in Fig. 9. From these graphs itis clear that these iron aluminum oxide nanoparticles show ferromagnetic behavior.Nanoparticles prepared for 5 - 15 minutes oxidation time show slight variation insaturation magnetization, coercivity, retentivity and squareness for in- and out-plane.

SampleNo.

Oxidationtime(min)

Latticeconstant(Ǻ)

Unitcellvolume(Ǻ3)

X-raydensity(gm/cm3)

Crystallitesize(nm)

Dislocationdensity(1×1015 m-

2)1 5 8.163 544.93 4.236 20.9 2.892 10 8.158 542.93 4.252 22.4 1.993 15 8.158 542.93 4.252 22.4 1.99

Fig.9 M-H curve for iron aluminum oxide nanoparticles at the room temperature withoxidation time

The trend of saturation magnetizationvariation in magnetic behaviorphase causes restructuring. In additincreased as oxidation time was increased tosaturation magnetization.

Fig. 10 Effect of oxidation time on the saturation magnetization of ir

H curve for iron aluminum oxide nanoparticles at the room temperature withoxidation time (a) 5 minutes (b) 10 minutes (c) 15 minutes

The trend of saturation magnetization for nanoparticles is shownmagnetic behavior is due to the presence of Al2O3 phase

causes restructuring. In addition, as it was observed in Fig. 4idation time was increased to 15mins. This will also

Effect of oxidation time on the saturation magnetization of iron aluminum oxidenanoparticles

H curve for iron aluminum oxide nanoparticles at the room temperature withs (c) 15 minutes

shown in Fig. 10. Thephase since impurity

as it was observed in Fig. 4, crystallite sizelead to increase in

on aluminum oxide

The variation of coercivity with respect to oxidation time is represented in Fig. 11.The value of coercivity increased at oxidation time of 10 minutes and after that it starteddecreasing. This random behavior is due to crystal imperfection.

Fig.11 Effect of oxidation time on the value of coercivity of iron aluminum oxidenanoparticles

The remanant magnetization also depicts random behavior. The random behaviorof retentivity of iron aluminum oxide nanoparticles is represented in Fig. 12. The lowestvalue of retentivity is observed for the oxidation time of 5 minutes for out-plane direction.

Fig. 12 Remanance of iron aluminum oxide nanoparticles

The squareness is the ratio of remnant magnetization to saturation magnetization.Usually it is observed that lower the value of squareness more the sample will beisotropic. The variation of squareness with respect to oxidation time is represented byFig. 13.

Fig. 13 Squareness of iron aluminum oxide nanoparticles

Variation of coercive field Hc, Saturation magnetization Ms, Squareness Mr/Ms,remnant magnetization Mr with oxidation time is listed in table 2.

Table 2: The variation in values of Coercivity Hc, Magnetization Ms, Remanance Mr andsquareness with oxidation time.

SampleNo.

Oxidation time(min)

CoercivityHc

(G)

SaturationMagnetization

Ms

(×10-3 emu)

RemananceMr

(×10-6 emu)

SquarenessSQ

In-plane

Out-plane

In-plane

Out-plane

In-plane

Out-plane

In-plane

Outplane

1 5 702.25 579.36 1.03372

1.0527

179.97

155.97 0.12 0.11

2 10 749.84 719.35 1.00806

1.0403

176.83

166.60 0.118

0.13

3 15 709.12 670.80 1.04920

1.0791

177.98

163.14 0.124

0.12

4. CONCLUSIONS

In this research work, low cost and application oriented technique of electro-deposition was used to deposit iron aluminum oxide nanoparticles at room temperature.Oxidation time was varied in the range 5-15 minutes while the deposition time was keptconstant at 10 minutes. Structural and magnetic properties of electrodepositednanoparticles were investigated as a function of oxidation time. By varying the oxidationtime, crystallinity and purity of iron aluminum oxide changed. Nanoparticles oxidized for10-15 minutes showed lattice parameters closely matched with standard values. Ironaluminum oxide nanoparticles exhibited strong ferromagnetic behavior. Highest valueof saturation magnetization was observed for the oxidation time of 15 minutes.

REFERENCES

Bas, J.A., Calero, J.A. and Dougan, M.J. (2003), “Sintered soft magnetic materials,properties and applications”, J. of Phys., 36, 167-181.

Booker, R. and Boysen, E. (2005), “Nanotechnology” Wiley, 78-90.Cullity, B.D. (1956), “Elements of X-ray Diffraction”, Addison-Wesley Publishing

Company, USA, 79-80.Holland, L. (1965), “Thin Film Microelectronics”, Chapman and Hall Ltd. London, 80-89.Kim, M., Sun, F., Lee, J. and Ki, H.L. (2010), “Influence of ultra-sonication on the

mechanical properties of Cu/Al2O3 nanocomposite thin films duringelectrodeposition”, Surf. Coat. Tech., 205, 2362–2368.

Krifa, M., Mhadhbi, M., Escoda, L., Saurina, J., Suñol, J.J., Llorca-Isern, N., Artieda-Guzmán, C. and Khitouni, M. (2013), “Phase transformations during mechanicalalloying of Fe–30% Al–20% Cu”, Powd. Tech., 246, 117–124.

Kumar, N., Sharma, V., Parihar, U., Sachdeva, R., Padha, N. and Panchal, C.J. (2011)“Structure, optical and electrical characterization of tin selenide thin films depositedat room temperature using thermal evaporation method,” J. Nano- Electron. Phys., 3,117-126

Maissel, L.I. (1970), “Hand book of Thin Film Technology”, McGraw-Hill, New York, 25-30.

Paesano, A., Matsuda, C.K., Cunha, J.B.M. da., Vasconcellos, M.A.Z., Hallouche, B.and Silva, S.L. (2003), “Synthesis and characterization of Fe-Al2O3 composites”, J.Magn. Magn. Mater., 264, 264–274.

Shinde, S.S., Bansode, R.A., Bhosale, C.H. and Rajpure, K.Y. (2011), “Physicalproperties of hematite - Fe2O3: application to photoelectrochemical solar cells”, J.Semicon., 56, 209-210.

Shwarsctein, A.K., Huda, M.N., Yan, Y., (2010), “Electrodeposited Aluminum-Doped r-Fe2O3 Photoelectrodes: Experiment and Theory”., Chem. Mater.,22, 510–517.

Siddique, M. and Riaz, M. (2010), “Stability of modified alumina with Fe2O3 at hightemperatures”, Phy. B., 405, 2238–2240.

Sikandar, H., Gul, R. and Jooa, S. (2012), “Influence of potential, deposition time andannealing temperature on photo electrochemical properties of electrodeposited ironoxide thin films”, J. Alloys. Comp., 520, 232– 237.

Thiemiga, D., Bunda, A. and Talbot, B. (2009), “Influence of hydrodynamics and pulseplating parameters on the electrodeposition of nickel–alumina nanocomposite films”,Electrochem. Acta., 54, 2491–2498.

Wilson, M., Kannangara, K., Smith, G., Simmons, M. and Burkhard, R. (2002),Nanotechnology: Basic Science and Emerging Technologies, Chapman andHall/CRC

Xu, J.L., Zhang, J., Shi, Z.N., Gao, B.L., Wang, Z.W., Hu, X.W. (2014), “Currentefficiency of recycling aluminum from aluminum scraps by electrolysis,” Transactionof Nonferrous Metal, Society of China, 24, 250-256.